James Boswell may have been inclined to use snuff, given his numerous vices and that he, at least at some point in his youth, disliked actually smoking tobacco. His opinion concerning smoke did change over time, though - even over short time. In one of his "notes to myself" dated August 12, 1763 in Leyden, Holland he wrote "Don't smoke any more because it makes you sick and a foreigner need not do it" - a reference to the Dutch habit of smoking a pipe. On January 21, 1764, however, then in Utrecht he wrote one of his many verses:

With the same ease that blackguards feed on tripeHave I, James Boswell, learnt to smoke a pipe:For I am now a very Dutchman grown, As all at Utrecht cannot fail to own.My father smoked full thirty years ago,And I most wisely in his footsteps go.While in my grate the wood is blazing seen,Upon a table I my elbow lean,And with a visage most composed and bluff,Steams of tobacco solemnly I puff.

I can't remember any explicit references to the use of snuff - or even other references to the use of tobacco - in his journals, but I'll make a note if it, if I find anything, and write about it here. Or perhaps somebody else knows more about it?